摘要:
A magnetic resonance (MR) system and method for generating information about an object is provided. The MR system comprises at least one MR detector configured to sense a plurality of electromagnetic signals and a modulator coupled to the MR detector and configured to modulate optical signals with the electromagnetic signals to generate corresponding modulated optical signals. The MR system further comprises a resonant matching circuit configured for matching an impedance of the MR detector to an impedance of the modulator to achieve at least one of a voltage gain or a noise performance. An optical conduit coupled to the modulator is configured to transmit the modulated optical signals from within a shielded environment to outside the shielded environment. A signal detector coupled to the optical conduit is configured to convert the modulated optical signals to electrical signals.
摘要:
A remote control system for a modulatable device is provided. The remote control system comprises a receiver system coupled to the modulatable device and configured to obtain an output characteristic of the modulatable device, the receiver system being located remotely with respect to the modulatable device. The system further comprises a command signal setting system coupled to the receiver system and configured to use the output characteristic to generate a drive command signal and a bias system coupled to the command signal setting system and configured to receive the drive command signal and set a bias point of the modulatable device based on the drive command signal. The bias system is located locally with respect to the modulatable device. The command signal setting system and the bias system are coupled via a first optical conduit.
摘要:
An optical sensor interrogation system comprises: a multi-frequency optical source configured to generate an optical interrogation signal, at least one optical sensor configured to filter light at a wavelength corresponding to a value of a sensed parameter and generate an optical sensor data signal, a photodetector configured to detect a reference signal and the optical sensor data signal and generate an electrical difference frequency signal corresponding to a wavelength difference between the reference signal and the optical sensor data signal, and an electrical frequency measurement module configured to measure the electrical difference frequency.
摘要:
A remote control system for a modulatable device is provided. The remote control system comprises a receiver system coupled to the modulatable device and configured to obtain an output characteristic of the modulatable device, the receiver system being located remotely with respect to the modulatable device. The system further comprises a command signal setting system coupled to the receiver system and configured to use the output characteristic to generate a drive command signal and a bias system coupled to the command signal setting system and configured to receive the drive command signal and set a bias point of the modulatable device based on the drive command signal. The bias system is located locally with respect to the modulatable device. The command signal setting system and the bias system are coupled via a first optical conduit.
摘要:
A magnetic resonance (MR) system and method for generating information about an object is provided. The MR system comprises at least one MR detector configured to sense a plurality of signals within a shielded environment and a digitizing circuit configured for digitizing the analog signals to generate digital signals. The MR detector, digitizing circuit is located within a shielded environment. The system further comprises a first transmission element configured for transmitting the plurality of digital signals to a plurality of electronic devices.
摘要:
A method is provided and includes exciting a sensor with an incident signal and generating a reflected signal by reflecting the incident signal from the sensor. The incident signal and the reflected signal interfere to form a standing wave. The method also includes processing the signals to determine a sensed parameter based upon a frequency at which the standing wave exhibits a null.
摘要:
A spread spectrum communications system that is operable to provide user-selectable data transfer rates comprises a user station for generating an access request and a gateway server for receiving the access request. The gateway server includes a rate unit for comparing a requested rate to assigned rates, a selector for selecting an available user channel and an available signaling alphabet, and an allocation unit for assigning the carrier, user channel, and alphabet to the access request. One of several offered transfer rates is assigned to the available user channel. Each offered rate corresponds to a set of signaling alphabets with low cross-correlation for data transfer.
摘要:
A direct sequence spread spectrum signal processing system permits the receiver to be turned off during most of the acquisition phase of reception to significantly reduce the on time of the associated receiver front end. Power requirements are further reduced by use of very low power high accuracy time and frequency circuits in GPS based tracking units. The microprocessor based GPS tracking system is shut down almost all the time, using extremely little electrical power, and is powered up for very short periods of time at scheduled intervals by an extremely low power clock circuit with accuracy that varies with temperature. Each time the microprocessor is powered up, system temperature is recorded in memory. At times when the microprocessor is powered up, the GPS system is accessed and the GPS standard time is read. The difference between the low power clock circuit based time and the GPS based time is correlated with the recorded temperature history. A correction table, built from this data, provides a temperature history based correction to the low power clock based circuit without reference to the GPS system, and provides a highly accurate time standard. An additional table constructed in the microprocessor temperature compensates the local frequency standard used for frequency synthesis in satellite communication channels. This table is constructed by measuring offset between the calculated and actual synthesized frequency required to lock onto the satellite transmitted reference (pilot tone), and correlating this measured offset with the system ambient temperature.
摘要:
A dc-free coding scheme that also provides channel gain employs a code that is based on an alphabet of two and comprises a list of N-dimensional vectors, where N is even, with a maximum run of two symbols. From this list, all vectors which begin or end in two identical symbols are eliminated. This avoids runs of longer than two consecutive symbols when vectors are concatenated. With this scheme, if the baseband transmission of a “+” is realized with positive voltage V and transmission of a “−” is realized with a negative voltage −V, then any concatenation of symbols is dc-free. Improved coding gain is realized by mapping modulated signals onto convolutional code trellises.
摘要:
A method for activating an optical article includes providing an optical article, wherein at least one mark is disposed on the optical article, wherein the mark comprises an optical-state change material in an initial state, the initial state preventing the optical article from being read by a player; deriving an unlock code by cryptographic operations on an optical article operatively coupled with a POS equipment and a data input from a medium encrypted with a cryptographic algorithm; deriving a toggling signal from an unlock code, and applying the toggling signal to the at least one mark resulting in changing the optical-state change material to a final state, the final state allowing the optical article to be read by the player; wherein the toggling signal comprises a set of values corresponding to the respective states of each of a plurality of marks on the surface of the optical article, and wherein applying the toggling signal results in setting each of the marks to either one of an initial state or a final state, corresponding to the value for the mark in the toggling signal.